In many manufacturing and food processing environments, it is necessary for quality assurance and other purposes to measure accurately the thickness of a small, thin item. For example, oats are processed into a variety of forms for use as a breakfast cereal, including old-fashioned or large flake rolled oats, quick oat flakes, and instant oatmeal. Old-fashioned oats are made of rolled oat groats (dehulled oat kernels) and are prepared to make oatmeal by cooking in boiling water for up to thirty minutes. Quick oat cereal consists of flakes made by rolling cut groats thinner than old-fashioned oat flakes. Quick oat flakes are prepared by cooking in boiling water for 1 to 15 minutes. Instant oatmeal is similar to quick oats but with additional treatments, such as the addition of a hydrocolloid gum to accelerate hydration. Instant oatmeal is prepared by adding hot water and stirring, without any additional cooking being required. Instant oatmeal may also be prepared by adding cold water and heating the mixture briefly in a microwave oven.
The production of old-fashioned oats and quick oat flakes is essentially the same, except for the starting material. Old fashioned oats start with whole groats and quick oats start with steel-cut groats. After being steamed, both are then rolled between two metal rollers, the spacing of which is adjusted to produce the flake thickness required for each product. Quick oats are rolled thinner than old-fashioned oats so that they will cook faster. For instant oatmeal, the flakes are rolled even thinner than for quick oats. Generally, quick oats have a thickness in the range of about 0.015 to 0.022 inches, while old-fashioned oats may have a thickness of up to about 0.05 inch.
For quality assurance purposes, it is necessary to sample oats from a production run and measure their thickness. A fairly uniform flake thickness is desirable in each processed batch of flakes to, for example, assure uniform cooking times and deliver the desired consistency and texture in the final cooked cereal product.
Previously, measurements of this type were done manually using a micrometer. Since this was done by hand, the process was time-consuming, labor-intensive and inconvenient. Further, measurements were prone to being both inaccurate and inconsistent for several reasons. The micrometer compresses the flake, and depending on the pressure applied could yield inaccurate results. Further, the pressure applied could vary not only from flake to flake, but also due to different techniques used by different human operators. Although some automated approaches have been proposed and represent an improvement over the manual approach, such approaches suffer other shortcomings, such as their inability to handle overlapping flakes and difficulty in accurately measuring curved flakes.